Work-driving device



Nov. 13', 1928. 1,691,144 J. BATH WORK DRI VI NG DEVICE Original FiledDec. 2 1921 2 Sheets-Sheet 1 111 III 107 [we/750k 1 H omg s Nov. 13,1928.-

J. BATH WORK DRIVING DEVICE Original Filed Dec. 27. 1921 2 Sheets-Sheet2 1Z0 (3! v [wenfar omg/s Patented Nov. 13, 1928.

"ran some PATENT OFFICE.

JOHN BATH, OF WORCESTER, MASSACHUSETTS.

wonx-nnivxno DEVICE.

Original application filed December 27, 1921, Serial No. 524,817 Dividedand this application filed December 14, 1925. Serial No. 75,201. i

This application is a divisipn of my prior application Serial No;52%,811, filedDece n- 'ber 27, 1. 21. and relates to a device tordrivinsrotating work. Whilethe device 1s capable of general ap'ilication, 1t 1s partlcularly adapted for use in "engine lathes,threading machines; thread grindlng machines and other similarapparatus.

The general object of my inventi1 1s to 10 provide a work driving devicewhich ls eftective to turn the work in either direction, and to providemeans by which the baclclash in the machine, 011 reversal, may beaccurately determined and by which it may be taken up in the WOI'Kdriving device.

F1 g. 1 is a sectional elevation of my work driving; device taken alongthe line 11 in l ig. 7; 1 i

iii 2 is a partial plan view looking in the direction of the arrow 2 inF1 1;

P's 8 4 5 and 6 are detail sectional. views taken respectively along thelines 88, 41- 4, 55, 0-6, of Fig. 7;

Fig. 7 is an end elevation of the taco plate and work drivingattachments;

Fig. 8 is a plan view of certain parts of the machine, illustrating themeans by which the amount of back lash is determined; and

9 is an end elevation looking in the direction of the arrow 9 in Fig. 8.

l: have shown my invention as applied to a thread grinding machine. Myimproved work drivingdcvice comprises ausual face pl to. 105 which isthreaded on the end of a spindle 60 (Fig. 1) rotatable in a head stock32. The plate 105 isprovided with a hub or extension 106 on which ismounted a ring 107' supporting a pair of work driving dogs 108. Thesedogs are radially adjustable on the ring 107 and are secured thereto bybinding screws 109. The inner ends of the dogs are shaped to receive andengage the shank of a tap or other articlcto be ground, which is held onthe head and tail centers of the machine.

The ring 1071s flanged and is held against the :t'uce plate by anouterring 110 secured to the face plate by binding screws 111. and 112(1 igs. 7 and 9). A slot 113 extends nearly around the ring 110 and thebinding screw 111 is shown as extending; through this slot, while thescrew 112 extends through a hole in the ring 110 between the ends of theslot 113. A series of tapped holes 114: may be the blocks provided inthe face plate to receive the screws 111 and 112.

Segmental blocks 115 and 116 (Figs. 4 and '1') are provided with curvedribs'or projections 117' (Fig-f 5) fitting the segmental slot 113. Theseblocks are secured in anguiarly adjusted position by clamping bolts 118and nuts 119 (Fig. 1). A spring handle 120 (F 1g. 7) is secured to eachblock 115 or 116 and is provided with aspur 121 (Fig. 5) en agingnotches 110 (Figs. 7 and, 9) iormed at the outer edge of the ring 110.-

A similar spring handle 122 (Fig. 9) is securei to the inner ring 107,this handle being provided with a socket or recess 123 adapted toreceive pins or studs 124 formed on'the ends of the bolts 118 whichsecure theblocks 115 and 116 in posi ion. Stops 125 and 126 (Figs. 3 and7) are also slidable in the slot 113 of the ring 110 and may be clampedin position as will be hereinafter described.

In the operation of my improved machine 115 and 116 are so located thatthe movement of the handle 122 from one pin or stud 1241 to the otherwill cause an angular movement oil the dogs 108 exactly equal to theback lash-in the connections between the work spindle and the grindingwheel table. The extent of this angular adjustment ofthe work requiredwith a particular set-up of the machine is determined experimentally byuse of the indicating device shown in Figs. Sand 9. Y

An arm 180 (Fig. 8) is fixed on the, wheel carriage (not shown) andextends forwardly and upwardly to a position for engagement by. theshort end of an index lever 131, pivotcd at 132 on a stand 133. Thestand is adjustably secured to the head stock 32 by a clamping belt 184.Alock plate 135 is slidably mounted inguide-ways 136 on the head stock32 and may be secured in adjusted position. by a clamping bolt 137. Anindex or zero line is formed on one of the guide-Ways- 136 referencemark torthe index lever 131.

In order to determine the exact amount of back lash in the connectionsbetween the spindle and thew heel carriage, the spindle is niovedin thedirection in which ithas been rotating until the handle 122 of thedogsupporting ring 1071s aligned with the jaws of the lock plate 135.This plate is then advanced in its guide-ways 186 until itrej leases thehandle from the pin or stud 1241 on which it has been seated and looksit from further angular movement. The stand 133 of the index lever orpointer 131 is then adjusted so that the rear end of the pointer will bepressed against the arm 130 by the pointer spring 188, while at the sametime the end ofthe pointer co-incides with the Zero mark on theguide-way 136.

The spindle 60 is then turned backward or in the opposite direction tothat in which it has been rotating until the wheel carriage begins tomove, such movement being inthat the wheel when thus adjusted engagesslightly harder on one side than on the other, one of the blocks 115 or116 may be further adjusted by moving its handle 120 one or more notchesalong the ring .110.

When adjustment is once made for a particular set-up of the machine, nofurther attention .is necessary beyond swinging the handle 122 from onestud 124 to the other at each end. of the wheel travel. The output ofthe machine is thus greatly increased, as the usual idle returnteed ofthe grinding wheel is entirely avoided.

When grinding certain types of thread, such as the Acme thread, it issometimes desirable to feed the wheel sideways to widen the threadgroove. The stops 125 are then used to preserve the original setting sothat the slides 115 or 116 may be moved the required number of notchessidewaysto, widen the thread and may then be returned to their originalpositions when a new thread is to. be ground and widened.

The face plate 105 may be provided with graduations as shown in Fig. 2and the ring 110 may have an index mark co-operatlng therewith toindicate the angular relation .of these parts.

These graduations are usetul when it is desired to advance the ring acertain angular amount relative to the faceplate.

Having described the construction and operation of my improved workdriving de vice, it will be-seen that I have provided a simple andefiective means for accurately determiningthe back lash in a machine,such as a thread grinding machine, and "for taking up the work lash uponthe reversal'of the machine, thus making the machine operative for manypurposes on both forward and backward travel and eliminating the idlereturn stroke.

Having thus described my invention and the advantages thereof, I do notwish to be limited tothe details herein disclosed otherwise than as setforth in the claims but what I claim is 1. In a thread grinding machine,a head stock, a work supporting spindle rotatable therein, a workdriving member mounted thereon, and means on said head stock eifece tiveto release said member from said spindle and to hold said releasedmember in fixed angular position.

.2. In a thread grinding machine, a work spindle, a face plate, a pairof driving dogs, a ring supportin said dogs, said ring being rotatablymounted on said plate, an

arm on said ring, and a pair of locating devices, angularly ad ustablevon said plate and means to hold said devices in fixed relation to saidplate after selective adjustment thereon, saiddevices thereafterco-operating with said arm to retain said ring and dogs in either one oftwo selected and definite angular positions.

3. In a thread grinding machine, a work spindle, a face plate, apair ofdriving dogs,

a ring supporting said dogs, said ring being I rotatably mounted on saidplate, and means to adjust and secure said ring on said plate, saidmeans including a spring arm on said ring and a toothed member securedto said face plate, the teeth of said member cooperating with said armto determine the position of said ring.

4. In a thread grinding machine, a work spindle, a face plate, a pair ofdrivingdogs,

a ring supporting said dogs, said ring be-' ing rotatably mounted onsaid plate, a pair of locating blocks, spring arms on said ring andblocks, a member secured to said plate and having teeth engaged by saidarms to position the same, and additional position-- ing devices on saidblocks co-operating with the arm on said ring.

p 5. A work driving device comprising a work spindle, a supportingmember rotatable therewith, w'ork engaging. elements mounted on saidsupporting member, means to simultaneously adjust all of said engagingelements angularly relative to said supporting member, means forlimiting the angular adjustment of said engaging elements, means forpositively fixing the limiting positions, and meansto determine slightadditonal angular adjustments relative to said positive limiting means,

In testimony whereof I have hereunto affixed my signature. a JOHN BATH.

